Resumen: Designing metal sites into de novo proteins has significantly improved, recently. However, identifying the minimal coordination spheres, able to encompass the necessary information for metal binding and activity, still represents a great challenge, today. Here, we test our understanding with a benchmark, nevertheless difficult, case. We assemble into a miniature 28-residue protein, the quintessential elements required to fold properly around a FeCys4 redox center, and to function efficiently in electron-transfer. This study addresses a challenge in de novo protein design, as it reports the crystal structure of a designed tetra-thiolate metal-binding protein in sub-Å agreement with the intended design. This allows us to well correlate structure to spectroscopic and electrochemical properties. Given its high reduction potential compared to natural and designed FeCys4-containing proteins, we exploit it as terminal electron acceptor of a fully artificial chain triggered by visible light. Idioma: Inglés DOI: 10.1038/s41467-023-37941-8 Año: 2023 Publicado en: Nature communications 14, 1 (2023), 2368 [11 pp.] ISSN: 2041-1723 Factor impacto JCR: 14.7 (2023) Categ. JCR: MULTIDISCIPLINARY SCIENCES rank: 8 / 134 = 0.06 (2023) - Q1 - T1 Factor impacto CITESCORE: 24.9 - Physics and Astronomy (all) (Q1) - Biochemistry, Genetics and Molecular Biology (all) (Q1) - Chemistry (all) (Q1)